Electronic controller

ABSTRACT

Provided is an electronic controller which enables visual identification of a portion applied with a small amount of a sealing material, which has a high possibility of air leakage from an area in which a joint is to be established. The electronic controller includes: an electronic circuit board; and a casing including a cover ( 1 ), a base ( 4 ), and a lid sealed with a sealing material ( 20 ) applied to surfaces thereof at which the cover ( 1 ), the base ( 4 ), and the lid are to be joined together. An area in which the cover ( 1 ), the base ( 4 ), and the lid are to joined together is provided with a space ( 16 ) thereto for enabling an application state of the sealing material ( 20 ) to be observed with a naked eye.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No. 13/460,086filed Apr. 30, 2012, which claims benefit of Japanese Patent ApplicationNo. 2011-246365, filed Nov. 10, 2011. These above-noted applications areincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic controller which includeselectronic components mounted on an electronic circuit board housedwithin a casing.

2. Description of the Related Art

An electronic controller, which is used for controlling a vehicle or thelike, includes an electronic circuit board, a plurality of electroniccomponents, and a casing. On the electronic circuit board, connectorsfor electrical connection to the exterior are provided. The plurality ofelectronic components are mounted on the electronic circuit board. Thecasing is made of a resin or a metal. The electronic circuit board ishoused in the casing for protection of the electronic components.

Among various types of electronic controller, an electronic controllerprovided in an engine room or directly mounted on an engine has awater-proof structure in view of a possibility of getting wet withwater. As an example of the electronic controller described above, thereexists an electronic controller disclosed in Japanese Patent ApplicationLaid-open No. 2003-258454 (FIGS. 4 and 5).

The electronic controller described in Japanese Patent Application citedabove has the following structure. A casing including verticallyseparated members, that is, a base and a cover, is used to interpose anelectronic circuit board on which a connector is provided. A gap betweena peripheral wall end surface of the base and a flange portion of thecover is sealed with a water-proof sealing material.

A sealing structure at surfaces, at which the base and the connector,and the cover and the connector are to be respectively jointed together,is as follows. A groove is provided on the connector. A projectingportion is provided on the cover at a position corresponding to thegroove, whereas another projecting portion is provided on the base. Awater-proof sealing material is provided in the groove of the connector.In this manner, the gaps between the cover and the connector and betweenthe base and the connector are sealed.

In the electronic controller having the water-proof structure asdescribed in Japanese Patent Application Laid-open No. 2003-258454 citedabove, it is necessary to check a water-proofing property thereof by anairtightness test so as to ensure the water-proofing property after theassembly of the electronic controller.

In a case of electronic controllers using an adhesive or a liquidpacking as a sealing material, when an electronic controller which doesnot meet a predetermined standard because of a small application amountof the sealing material is found in the airtightness test for the casingof the electronic controller, it is necessary to additionally apply thesealing material from the exterior to an area of the casing, in which ajoint is to be established, and to conduct the airtightness test again.

In the case of the electronic controller described above, however, theapplication amount of the sealing material on the area of the casing, inwhich a joint is to be established, cannot be easily checked. Therefore,it is difficult to identify a portion from which air leaks,specifically, a portion which requires to be additionally applied withthe sealing material.

If, for example, complicated tasks such as immersing the electroniccontroller into a tank storing water therein and feeding air into theelectronic controller to identify the air leakage portion are performed,the air leakage portion can be identified. However, conducting suchtasks in a fabrication line for the electronic controllers is notpractical in view of a line space, capital investment, and fabricationcost.

As described above, the conventional electronic controllers have had aproblem in that it is difficult to identify a portion with a smallamount of the sealing material, which has a high possibility of airleakage, and to additionally apply the sealing material only to theidentified portion at the location of assembly.

As countermeasures against the aforementioned problem, it is possible toconceive of additionally applying the sealing material over the entireperiphery from the exterior of the casing of the electronic controller.In this case, however, there arises another problem in that the amountof the sealing material to be used disadvantageously increases, therebyincreasing the cost of the electronic controller.

SUMMARY OF THE INVENTION

The present invention has been made to solve the problems describedabove, and therefore, has an object to provide an electronic controllerwhich enables visual identification of a portion applied with a smallamount of a sealing material, which has a high possibility of airleakage from an area in which a joint is to be established, so as toreduce a reject ratio in an airtightness test and thus improve theefficiency of assembly operation by additionally applying the sealingmaterial to the visually identified portion before the airtightness testis conducted.

Further, the present invention has another object to provide anelectronic controller which enables the use of an appropriate amount ofthe sealing material and thus eliminates an unnecessary use of thesealing material by applying the sealing material only to the portionapplied with the small amount of the sealing material when the sealingmaterial is to be additionally applied.

An electronic controller according to the present invention includes: anelectronic circuit board having electronic components mounted thereon;and a casing for housing the electronic circuit board therein, thecasing including a plurality of casing members sealed with a sealingmaterial applied to surfaces at which the plurality of casing membersare to be joined together, in which an area in which the plurality ofcasing members are to be joined together is provided with a spacethereto for enabling an application state of the sealing material to beobserved with a naked eye from exterior in a state in which theplurality of casing members are joined together.

According to the electronic controller of the present invention, thespace enabling the application state of the sealing material to beobserved with the naked eye from the exterior, in a state in which thecasing members are joined together, is provided to the area in which thecasing members are to be joined together. Therefore, the portion appliedwith the small amount of the sealing material, which has the highpossibility of air leakage from the area in which the casing members areto be joined together can be visually identified. As a result, byadditionally applying the sealing material before the airtightness testis conducted, the reject ratio in the test can be reduced and theefficiency of assembly operation can be improved.

Further, by applying the sealing material only to the portion appliedwith the small amount of sealing material when the sealing material isto be additionally applied, the use of the appropriate amount of thesealing material can be attained, and thus the unnecessary use of thesealing material can be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is an exploded perspective view schematically illustrating astructure of an electronic controller according to Embodiment 1 of thepresent invention;

FIG. 2A is a sectional view of a principal part of a cover and a baseillustrated in FIG. 1 before the cover and the base are joined together;

FIG. 2B is a sectional view of the principal part illustrated in FIG. 1after the cover and the base are joined together;

FIG. 2C is a sectional view of the principal part of the cover and thebase, illustrating a variation of an area in which the cover and thebase are to be joined together;

FIG. 3 is a perspective view of one of claws illustrated in FIG. 1;

FIG. 4A is a sectional view of a principal part of a cover and a base ofan electronic controller according to Embodiment 2 of the presentinvention before the cover and the base are joined together;

FIG. 4B is a sectional view of the principal part of the cover and thebase after the cover and the base are joined together;

FIG. 5 is an exploded sectional view schematically illustrating astructure of an electronic controller according to Embodiment 3 of thepresent invention;

FIG. 6A is a sectional view of a principal part of a casing main bodyand a lid illustrated in FIG. 5 before the casing main body and the lidare joined together; and

FIG. 6B is a sectional view of the principal part of the casing mainbody and the lid after the casing main body and the lid are joinedtogether.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an electronic controller according to embodiments of thepresent invention is described with reference to the drawings. In thedrawings, the same or equivalent members or portions are denoted by thesame reference numeral for description.

Embodiment 1

FIG. 1 is an exploded perspective view schematically illustrating astructure of an electronic controller according to Embodiment 1 of thepresent invention.

The electronic controller includes an electronic circuit board 2 havingelectronic components 5 mounted thereon, and a casing which houses theelectronic circuit board 2 therein.

The casing includes a base 4, a cover 1, and a lid 30. The base 4 andthe cover 1 interpose the electronic circuit board 2 from both sides tocover the electronic circuit board 2. The lid 30 supports connectors 3,each being electrically connected to the electronic circuit board 2, andcloses an opening portion 36 formed by the base 4 and the cover 1.

Note that, the lid 30 and the connectors 3 may be formed as onecomponent instead of being formed as separate members.

In this embodiment, casing members constituting the casing are the base4, the cover 1, and the lid 30.

As a material of the cover 1, the base 4, and the lid 30, a metal havinga high thermal conductivity, such as aluminum, is desirable in view ofheat-radiation performance. However, when the heat-radiation performanceis not needed, other materials may be used.

Three sides of the base 4 having a rectangular shape and three sides ofthe cover 1 are joined together by using a sealing material 20. A lowerend of the lid 30 is joined to one side of the base 4 having therectangular shape by using the sealing material 20. An upper end of thelid 30 is joined to an inner peripheral portion of the opening portion36 of the cover 1 by using the sealing material 20. The opening portion36 has a trapezoidal shape.

The sealing material 20 is applied to grooves 10 and 11. The groove 10is formed along four sides of the base 4, whereas the groove 11 isformed along upper three end surfaces of the lid 30.

FIG. 2A is a sectional view of a principal part of the cover 1 and thebase 4 illustrated in FIG. 1 before the cover 1 and the base 4 arejoined together, whereas FIG. 2B is a sectional view of the principalpart of the cover 1 and the base 4 illustrated in FIG. 1 after the cover1 and the base 4 are joined together.

A projection 12 is formed over the entirety of a lower end of the cover1. The projection 12 is formed so as to be bent at a base thereof. Awidth W1 of the projection 12 is smaller than a width W2 of the groove10.

When the cover 1 and the base 4 are to be joined together, an inner wallsurface 39 of the projection 12 comes into surface contact with an innerwall surface 34 of the groove 10 of the base 4. Then, the projection 12is lowered in this state. In this manner, the projection 12 presses andflattens the sealing material 20 applied to the groove 10.

As illustrated in FIG. 2B, when the cover 1 and the base 4 are joinedtogether, the sealing material 20 is pushed to flow into a space 16formed by a difference between the width W2 of the groove 10 and thewidth W1 of the projection 12 of the cover 1. The space 16 is aclearance formed in an area in which the cover 1 and the base 4 are tobe joined together when the projection 12 is inserted into the groove10.

Therefore, through the space 16 formed in the area in which the cover 1and the base 4 are to be joined together, an application state of thesealing material 20 can be checked with the naked eye in a state inwhich the cover 1 and the base 4 are joined together.

In this example, the space 16 enabling the application state of thesealing material 20 to be checked with the naked eye from the exterioris provided so as to extend horizontally in parallel to the base 4.

Therefore, the application state of the sealing material 20 can beeasily checked in a comfortable posture without moving the casing.Accordingly, high workability during the checking is provided.

Further, the projection 12 of the cover 1 is lowered while the innerwall surface 39 thereof is held in surface contact with the inner wallsurface 34 of the groove 10. Therefore, the sealing material 20 does notflow into the interior of the casing and stays in the space 16 enablingthe application state of the sealing material 20 to be checked from theexterior. Accordingly, a portion with an insufficient amount of thesealing material 20 can be easily identified.

The space 16 formed in the area in which the base 4 and the cover 1 areto be joined together has an opening width for additionally applying thesealing material 20 from the exterior and functions as a space forstoring the sealing material 20 therein. Therefore, when the applicationamount of the sealing material 20 is small, additional application ofthe sealing material 20 can be easily performed through the space 16.

The opening width of the space 16 is larger than a diameter of a nozzle50 of sealing-material injection means for additionally applying thesealing material 20 from the exterior. The additional application of thesealing material 20 is performed while the nozzle 50 is oriented towardthe groove 10 through the space 16.

FIG. 2C is a sectional view illustrating an example where a space 16Afor checking the application state of the sealing material 20 isprovided so as to extend vertically.

In this example, a protruding portion 38 which extends horizontally isformed on the lower end of the cover 1. The space 16A is formed betweenthe protruding portion 38 and the base 4.

When the space 16A is provided vertically with respect to the base 4, ascompared with the case where the space 16 is provided horizontally, aspace for storing the sealing material 20 is secured in the verticaldirection, although it is necessary to move the casing to check thesurfaces at which the cover 1 and the base 4 are joined together inorder to check the application state of the sealing material 20.Therefore, the outer dimension of the casing can be designed smaller.Accordingly, the example with the space 16A is advantageous in terms ofreduction in size.

Note that, a color of the sealing material 20 may be set different fromthat of the cover 1, the base 4, and the lid 30, serving as the casingmembers constituting the casing, so that the application state of thesealing material 20 is more easily checked.

Further, a colorless and transparent material may be used for the cover1 so that the application state of the sealing material 20 is moreeasily checked in the areas in which the cover 1 and each of the base 4and the lid 30 are to be joined together.

In this case, the space in the areas in which the cover 1 and each ofthe base 4 and the lid 30 are to be joined together may be omitted.

FIG. 3 is a perspective view illustrating one of claws 13 provided tothe cover 1.

The claws 13 are formed on the lower edge of the cover 1 at threepositions.

A hole 14 is formed at a base of each of the claws 13. A locking portion37 is formed on the base 4 so as to correspond to the claw 13. The claw13 is elastically locked to the locking portion 37. In this manner, thecover 1, the base 4, and the lid 30 are prevented from being movedrelative to each other until the sealing material 20 is cured.

The hole 14 formed at the base is formed simultaneously with formationof the claw 13. Through the hole 14, the application state of thesealing material 20 can be checked, as in the case of the surfaces ofthe cover 1 and the base 4 at which the cover 1 and the base 4 are to bejoined together except for the claws 13.

The hole 14 has an opening width for additional application of thesealing material 20 and is also used as a space for storing the sealingmaterial 20 for the additional application as in the case of the space16 formed in the area in which the cover 1 and the base 4 are to bejoined together except for the claws 13.

Note that, a height of the sealing material 20 in the hole 14 may beused as a criterion for determining the application amount of thesealing material 20.

Therefore, even in portions with the claw 13, the application state ofthe sealing material 20 can be checked. Thus, the same effect as that ofportions without the claws 13 can be obtained.

Moreover, the hole 14 provided at the base of the claw 13 has theopening width enabling the additional application of the sealingmaterial 20. Therefore, workability during additional application of thesealing material 20 is improved.

Note that, the area in which the cover 1 and the lid 30 are to be joinedtogether has the same structure as that of the area in which the cover 1and the base 4 are to be joined together. Thus, the structure providessuch effects as enabling the application state of the sealing material20 to be checked with the naked eye, through the space formed in thearea in which the cover 1 and the lid 30 are to be joined, in the statein which the cover 1 and the lid 30 are joined together.

Embodiment 2

FIG. 4A is a sectional view of a principal part of the cover 1 and thebase 4 of an electronic controller according to Embodiment 2 of thepresent invention before the cover 1 and the base 4 are joined together,whereas FIG. 4B is a sectional view of the principal part of the cover 1and the base 4 after the cover 1 and the base 4 are joined together.

In this embodiment, a jetty 18 is provided to the cover 1 so as to beformed on an inner side of a projection 12A and be opposed to theprojection 12A. A dimension of the jetty 18 toward the base 4 is longerthan a dimension of the projection 12A toward the base 4.

The remaining configuration is the same as that of the electroniccontroller of Embodiment 1.

In this embodiment, before the projection 12A of the cover 1 presses andflattens the sealing material 20, an inner wall surface 40 of the jetty18 comes into contact with an inner wall surface 35 of the base 4, andthen the jetty 18 is lowered while blocking an inflow path of thesealing material 20 into the interior of the casing. Therefore, thesealing material 20 is prevented from entering the interior of thecasing.

Whereas two surfaces of the projection 12 are covered with the sealingmaterial 20 in Embodiment 1 as illustrated in FIG. 2B, all the surfacesof the projection 12A are covered with the sealing material 20 in thisEmbodiment 2. Therefore, a length over which the projection 12A is incontact with the sealing material 20 becomes correspondingly long ascompared with that in Embodiment 1. Accordingly, higher adhesionstrength and sealability between the cover 1 and the base 4 areprovided.

The remaining functions and effects are the same as those of theelectronic controller according to Embodiment 1.

Note that, the area in which the cover 1 and the lid 30 are to be joinedtogether has the same structure as that of the area in which the cover 1and the base 4 are to be joined together. Thus, the structure providessuch effects as enabling the application state of the sealing material20 to be checked with the naked eye, through the space formed in thearea in which the cover 1 and the lid 30 are to be joined together, inthe state in which the cover 1 and the lid 30 are joined together.

Embodiment 3

FIG. 5 is an exploded sectional view schematically illustrating astructure of an electronic controller according to Embodiment 3 of thepresent invention. FIG. 6A is a sectional view of a principal part of acasing main body 7 and a lid 30A illustrated in FIG. 5 before the casingmain body 7 and the lid 30A are joined together, whereas FIG. 6B is asectional view of the principal part of the casing main body 7 and thelid 30A after the casing main body 7 and the lid 30A are joinedtogether.

The electronic controller according to Embodiment 3 includes the casingmain body 7 and the lid 30A. The casing main body 7 is a casing memberwhich houses an electronic circuit board 2A therein. The lid 30A is acasing member which supports connectors 3A electrically connected to theelectronic circuit board 2A and closes an opening portion 36A of thecasing main body 7.

Note that, the lid 30 and the connectors 3A may be formed as onecomponent instead of being formed as separate members.

A groove 10A is formed on the casing main body 7 so as to surround theentire periphery of the opening portion 36A. The projection 12A isformed on the lid 30A so as to be opposed to the groove 10A, which is tobe applied with a sealing material 20A.

In this embodiment, when the lid 30A and the casing main body 7 are tobe joined together, an inner wall surface 39A of the projection 12A islowered while being held in surface contact with an outer peripheral endsurface 42 of the casing main body 7. In this manner, the projection 12Apresses and flattens the sealing material 20A applied to the groove 10A.

As illustrated in FIG. 6B, a space 16B is provided in an area in whichthe lid 30A and the casing main body 7 are to be joined together. Thesealing material 20A is pressed to flow into the space 16B. Through thespace 16B, an application state of the sealing material 20A can bechecked when the lid 30A and the casing main body 7 are joined together.

The space 16B for checking the state of the application of the sealingmaterial 20A to the groove 10A of the casing main body 7 has an openingwidth for additionally applying the sealing material 20A from theexterior, and functions as a space for storing the sealing material 20Atherein. Therefore, when the application amount of the sealing material20A is small, additional application of the sealing material 20A can beeasily performed through the space 16B.

The opening width of the space 16B is larger than the diameter of thenozzle 50 of the sealing-material injection means for additionallyapplying the sealing material from the exterior.

Note that, the groove 10 is formed on the base 4 and the projection 12is formed on the cover 1 in Embodiments 1 and 2 described above, but thegroove may be formed on the cover and the projection may be formed onthe base.

Further, the groove 10A is formed on the casing main body 7 and theprojection 12A is formed on the lid 30A in Embodiment 3 described above,but the groove may be formed on the lid and the projection may be formedon the casing main body.

Still further, the three casing members are used to constitute thecasing in Embodiments 1 and 2, and the two casing members are used toconstitute the casing in Embodiment 3. However, it is apparent that fouror more casing members may be used to constitute the casing.

What is claimed is:
 1. An electronic controller, comprising: anelectronic circuit board having electronic components mounted thereon;and a casing for housing the electronic circuit board therein, thecasing comprising a plurality of casing members sealed with a sealingmaterial applied to surfaces at which the plurality of casing membersare to be joined together, wherein an entire area in which the pluralityof casing members are to be joined together is provided with a spacethereto for enabling an application state of the sealing material to beobserved with a naked eye from exterior in a state in which theplurality of casing members are joined together.
 2. The electroniccontroller according to claim 1, wherein the space is provided so as toextend in a horizontal direction.
 3. The electronic controller accordingto claim 1, wherein a jetty for preventing the sealing material fromentering interior of the casing when a pair of the plurality of casingmembers are joined together is provided on an inner side of the area inwhich the plurality of casing members are to be joined together.
 4. Theelectronic controller according to claim 1, wherein at least one of theplurality of casing members has a groove and at least one of theplurality of casing members has a projection, and wherein a width of theprojection is smaller than a width of the groove such that when theprojection is inserted into the groove, a clearance space through whichthe application state of the sealing material to be observed is formed.5. An electronic controller, comprising: an electronic circuit boardhaving electronic components mounted thereon; and a casing for housingthe electronic circuit board therein, the casing comprising a pluralityof casing members sealed with a sealing material applied to surfaces atwhich the plurality of casing members are to be joined together, whereinan area in which the plurality of casing members are to be joinedtogether is provided with a space thereto for enabling an applicationstate of the sealing material to be observed with a naked eye fromexterior in a state in which the plurality of casing members are joinedtogether, and wherein, among a pair of the plurality of casing membersjoined together, a claw to be elastically locked to one of the pair ofthe plurality of casing members is provided to another one of the pairof the plurality of casing members, and a hole having the space forenabling the application state of the sealing material to be observedwith the naked eye from the exterior is formed at a base of the claw. 6.The electronic controller according to claim 5, wherein the space isprovided so as to extend in a horizontal direction.
 7. The electroniccontroller according to claim 5, wherein a jetty for preventing thesealing material from entering interior of the casing when a pair of theplurality of casing members are joined together is provided on an innerside of the area in which the plurality of casing members are to bejoined together.